Mega-fires obliterate whole ecosystems

Over the past decade, every forested continent has seen an alarming surge in mega-fires.  Really fast burning fires. And their local intensity is just amazing.… extraordinary fire events. … They totally demolish ecosystems that have thrived with fire for millennia. In the Southwest US, the fires have become so large and so intense that whole forests are transforming into entirely different landscapes.

The Las Conchas fire in the US  had stunning fire behaviour on the first day. It burned 43,000 acres in the first 14 hours. Almost one acre per second… The Las Conchas fire was outside the experience of anybody in New Mexico. The scale of that fire was almost quadruple the size of the previous largest fire. It was shocking to the fire people, they’d never seen this kind of fire . It was shocking to ecologists like myself as well ….

This used to be Ponderosa pine forest as far as the eye could see and you can hardley see any evidence that this was a forest.   The pine forest that was here was hit by two high severity fires – 15 years apart. The first killed the trees, the second erased even the blackened trunks.  … The Ponderosa forest had been here for thousands of years. …  Instead of trees, grasses and shrubs have moved in. At lower elevations, there’s barely any vegetation at all.

The first night of the Las Conchas fire an amazing thing happened. There was this huge convection cloud – these pyrocumulonimbus clouds from the heat. When the plume collapsed it just incinerated the above ground biomass … It burnt off the rich organic top portion of the soil leaving a  desertified landscape afterwards – a moonscape. This hurts a bit actually, personally. These are forests I’ve spent more than thirty years studying. Some of the individual trees are friends. … In the past, fires burnt much less severely, leaving living trees to regenerate the scorched areas, but as you can see behind me, for many thousands of hectares, there’s not a single living conifer left. And there won’t be, for hundreds of years to come.

And these fires are occurring in Australia too.

ABC Catalyst “Earth on Fire” 3 June 2014

Category: Extremes

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